The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, the semiconductor industry utilized various methods and structures to form driver circuits for light emitting diodes (LEDs). Some of the LED driver circuits were designed to received an analog control signal and generate an analog drive signal that linearly varied the current through the LED. One example of such a control circuit that was available from Fairchild Semiconductor Corp. of South Portland Me. was referred to by the part number FAN5611. In some applications, it was desirable to have other methods of controlling the current through the LED.
Accordingly, it is desirable to have an LED controller that can vary the current through an LED in more than one method in response to a control signal.
For simplicity and clarity of the illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain N-channel or P-Channel devices, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action.